The present invention relates to a touch panel, which has a light-shielding effect in its peripheral portion and is able to improve the visibility of its screen at low cost and also cope with a reduction in thickness of a product provided with an LCD with a touch panel.
Conventionally, an analog resistive film system touch panel, where conductive panels 201 and 202 are arranged opposite to each other with transparent electrodes 212 and 222 formed with the whole or a part of transparent conductive films and wiring lines formed on one-side surfaces of transparent insulative substrates 211 and 221, is arranged on the screen of a liquid crystal display (LCD) of a word processor, a personal computer, or the like. By effecting downward pressurization with a finger, a pen, or the like according to instructions seen through the screen, positional inputting is effected.
The above-mentioned analog resistive film system touch panel normally includes one or more resin layers for various purposes in its peripheral portion located between the transparent insulative substrates 211 and 221. One example of the above-mentioned resin layer, as shown in FIG. 4, has an adhesion layer 203 formed for the purpose of bonding the conductive panels to each other between the conductive panel 201 located on the touch input side and the conductive panel 202 located on the screen side. There are further included a wiring line overcoat layer 227, which is formed for the purpose of mutually insulating the wiring lines arranged parallel in the peripheral portions of a surface that has wiring lines of lead electrodes 223, routing circuits 224 and 225, connection electrodes 226, and the like of a conductive panel with interposition of a wiring oxidation inhibitor or a minute gap, an insulative is patterning layer 214 formed for the purpose of obtaining the transparent electrode 212 by insulating the peripheral portion of a surface that has on its entire surface the transparent conductive film 121 of the transparent insulative substrate 211, and so on.
Moreover, as an illuminator used for the LCD 6, a back light 7 is arranged on the back surface when the LCD 6 is a transmission type (see FIG. 5) or a front light 8 is arranged between the touch panels 5 and the LCD 6 when the LCD 6 is a reflection type liquid crystal (see FIG. 6). Either light is provided with a line light source 72 or 82 such as a cold cathode tube arranged on an end surface of its light guide plate 71 or 81 made of a transparent resin or the like. A beam of light taken in from the end surface of the light guide plate 71 or 81 is guided depthwise while being totally reflected inside the light guide plate 71 or 81, and a part of the light is emitted from one surface of the light guide plate 71 or 81 to illuminate the LCD 6.
In recent years, according to the dimensional reduction of products provided with an LCD with a touch panel of a word processor, a personal computer, or the like and the dimensional increase of their screens, the outside dimensions of the light guide plates 71 and 81 of the back light 7 and the front light 8 have come close to the screen dimensions of the products. As a result, a luminescent line has occurred in a portion located inside the screen near the edge on the line light source 72 or 82 side due to intense light, which has been incident from the line light source 72 or 82 to enter the light guide plate 71 or 81 and emitted as it is from the neighborhood of the line light source, and this has reduced visibility. Moreover, even with a side surface reflecting layer 73 or 83 provided on the side surface on which the line light source 72 or 82 of the light guide plate 71 or 81 has been absent, a luminescent line has similarly occurred in a portion located inside the screen near the edge on the side surface reflecting layer 73 or 83 side due to scatter reflections on the side surface reflecting layer.
Accordingly, there is presently taken a means for restraining the occurrence of the luminescent line by sticking a frame-shaped black light-shielding sheet 9 to the touch panel 5 (see FIG. 5 and FIG. 6), the back light 7, the front light 8, the LCD 6, or the like.
However, measures against the luminescent line needs the operation of preparing and sticking a black light-shielding sheet only for the measures against the luminescent line aside from the construction of the touch panel, the LCD, and so on, and this leads to a problem that the production cost costs high. Furthermore, the black light-shielding sheet is cut in a frame-like shape with its inside portion scrapped, and this leads to wastefulness.
Moreover, the total thickness of the product provided with an LCD with a touch panel, such as a word processor or a personal computer, has increased by the thickness of the black light-shielding sheet, and this has led to an issue that the arrangement has not been able to cope with the thickness reduction of the product.
Accordingly, an object of the present invention is to solve the aforementioned issues and provide a touch panel, which has a light-shielding effect in the peripheral portion and is able to improve the visibility of its screen at low cost and also cope with a reduction in thickness of a product provided with an LCD with a touch panel.
In order to achieve the aforementioned object, the present invention is constructed as follows.
In order to achieve the aforementioned object, according to a first aspect of the present invention, there is provided an analog resistive film system touch panel comprising:
conductive panels arranged opposite to each other with transparent electrodes having a light-shielding effect in its peripheral portion being formed by a whole or a part of transparent conductive films and wiring lines formed on one-side surfaces of transparent insulative substrates; and
a resin layer comprised of one or more layers located peripherally between the transparent insulative substrates of the conductive panels arranged opposite to each other,
wherein at least one layer of the resin layers serves as a light-shielding layer for shielding light while being colored black.
According to a second aspect of the present invention, there is provided the touch panel having a light-shielding effect in its peripheral portion as defined in the first aspect, wherein the light-shielding layer is an adhesion layer, which is arranged between the conductive panels and colored black so as to shield light.
According to a third aspect of the present invention, there is provided the touch panel having a light-shielding effect in its peripheral portion as defined in the first or second aspect, wherein the light-shielding layer is at least one layer of wiring line overcoat layers, said at least one layer being arranged on the wiring line located in a peripheral portion of the conductive panel and colored black so as to shield light.
According to a fourth aspect of the present invention, there is provided the touch panel having a light-shielding effect in its peripheral portion as defined in the first or second aspect, wherein the light-shielding layer is at least one layer of insulative patterning layers, said at least one layer being arranged on the transparent conductive film located in a peripheral portion of the conductive panel and colored black so as to shield light.
According to a fifth aspect of the present invention, there is provided the touch panel having a light-shielding effect in its peripheral portion as defined in the third aspect, wherein the light-shielding layer is at least one layer of insulative patterning layers, said at least one layer being arranged on the transparent conductive film located in a peripheral portion of the conductive panel and colored black so as to shield light.